Loud waterfall from tank

[reeflink]

it looks like you put either gate or ball valves behind the tank, do you have access to them to control the rate of water flow?

Yes there both adjusted

@reeflink These are the red valve controls in the center of your first picture and are probably difficult to reach now that the tank is in position. You probably have to reach over sump and around behind the stand up toward the top tank to see if you can reach the valve lever. They appear to be levered ball valves rather than knobbed gate valves?

You will want these to be easily accessible for dialing in drain/return rate ratios...

they are I designed the tank stand to pull the drawer out them. But I have a gate valve installed and have it tuned.

 

[reeflink]

It’s the sound overflowing from the inside of the tank into the inner part of the overflow not the outside

 

[Soren]

Yes there both adjusted

they are I designed the tank stand to pull the drawer out them. But I have a gate valve installed and have it tuned.

That is good that the drawer allows for access to the ball valves.
What do you mean that the gate valve is tuned? If you closed this gate valve entirely, the drain rate would drop significantly forcing the water level in the overflow to rise until it flows over the secondary and/or emergency drain enough to match the return rate. Of course, this is an extreme case to show the function of the different drains.

It’s the sound overflowing from the inside of the tank into the inner part of the overflow not the outside

I understand this, but is there a difference in water level between the inner and outer overflows? If the outer overflow is drained too fast in relation to the return rate, the inner overflow will never fill very full because the bulkheads between the two never fill up.

I have a ghost overflow with three drains in the same general configuration as you have and can fine-tune the amount of sound by limiting flow in the primary drain and maintaining a high-enough flow rate. Your return(s) should flow at a high enough rate to allow for the outer overflow to fill to the level of the bottom of the U on the secondary drain. This would allow for the internal overflow to also fill higher to limit the waterfall height to also limit sound.

Does the internal overflow weir have straight or slanted notches? My overflow made by Modular Marine has weir slots with a slope on the inside to allow water to flow down the inside rather than leap off the weir and crash down on the water in the interior overflow.

Hopefully this picture helps explain what I mean: Left side is straight-cut weir slots that allow for gap behind flow-over into interior overflow, Right side is bevel-cut weir slots that allow water to flow smoothly into interior overflow with much less chance for turbulence and open drop onto water surface.

 

[Dburr1014]

It’s not in the sump or the back of the overflow but from the tank to the inner box slotted portion of the overflow

It's the 2nd drain that will raise the level. Raise it up. Less of a fall, less of a noise.

 

[JNalley]

So, either the siphon has air in it, causing a waterfall sound, or the Durso needs to go up about an inch. If it is indeed the sound of the water going into the overflow box, then it's the latter, the bottom of the Durso line needs to be above the opening of the bulkhead I believe (The orange line in the image below)

 

[Soren]

It’s the sound overflowing from the inside of the tank into the inner part of the overflow not the outside

Try increasing your return rate and slowly partially closing the gate valve on the primary drain until water level in the overflow reaches the height of the U on the secondary drain. This should bring the water level up in the interior overflow compartment as well.

Alternatively, you could try adding sponge material inside the top of the interior overflow to break up the flow and allow it to fall more gently into the overflow rather than cascading down. I did this in the overflow in my 75-gallon tank with 75-gallon sump setup to prevent my small cleaner gobies from swimming through. I suspect this sponge will prove troublesome, though, as drain flow will become impeded over time as the sponge becomes clogged and limits water movement through overflow. This could result in flooding, since it could stop overflow before the return water can reach the emergency drain.

 

[Dburr1014]

Personally, I would lose the 2ndary "u" pipe. Take it off temporary or permanently until you see how this drain type works.
You need a full syphone in the main drain. But it has to be lower that the 2nd so you don't get the whirlpool effect. But the 2ndary to be high enough so the water thru the weir does fall more than .5/1".
Main drain should also be under water in the sump so you don't get that loss splash noise. And it's better to have the gate valve close to the sump.

 

[reeflink]

That is good that the drawer allows for access to the ball valves.
What do you mean that the gate valve is tuned? If you closed this gate valve entirely, the drain rate would drop significantly forcing the water level in the overflow to rise until it flows over the secondary and/or emergency drain enough to match the return rate. Of course, this is an extreme case to show the function of the different drains.


I understand this, but is there a difference in water level between the inner and outer overflows? If the outer overflow is drained too fast in relation to the return rate, the inner overflow will never fill very full because the bulkheads between the two never fill up.

I have a ghost overflow with three drains in the same general configuration as you have and can fine-tune the amount of sound by limiting flow in the primary drain and maintaining a high-enough flow rate. Your return(s) should flow at a high enough rate to allow for the outer overflow to fill to the level of the bottom of the U on the secondary drain. This would allow for the internal overflow to also fill higher to limit the waterfall height to also limit sound.

Does the internal overflow weir have straight or slanted notches? My overflow made by Modular Marine has weir slots with a slope on the inside to allow water to flow down the inside rather than leap off the weir and crash down on the water in the interior overflow.

Hopefully this picture helps explain what I mean: Left side is straight-cut weir slots that allow for gap behind flow-over into interior overflow, Right side is bevel-cut weir slots that allow water to flow smoothly into interior overflow with much less chance for turbulence and open drop onto water surface.

Mine are flat as in the first picture

 

[reeflink]

Mine are flat as in the first picture

I have fine tuned the gate valve at higher return flow band keep the levels high enough but it makes louder sounds because of the flow forcing through the wier slots (waterfall effect)

 

[Dburr1014]

I have fine tuned the gate valve at higher return flow band keep the levels high enough but it makes louder sounds because of the flow forcing through the wier slots (waterfall effect)

How far is the water falling? Measure it with a ruler.

 

[reeflink]

How far is the water falling? Measure it with a ruler.

It’s falling 1.25”

 

[Dburr1014]

To far

 

[Dburr1014]

You need to raise up secondary drain to make that falling distance less than 1 inch. Closer to half inch would be better

 

[JNalley]

It’s falling 1.25”

these need to be fully submerged, the only way to do that is to raise the durso up.

 

[Dburr1014]

these need to be fully submerged, the only way to do that is to raise the durso up.

There should be at least probably 4 inch between the primary drain and a secondary drain. This way you don't get that Cyclone sucking sound.
The second thing is the secondary drain if it's raised up will raise that water level inside that little box so the water doesn't fall in 1.25 off the weir.
Like I said before, lose that "u" shaped pipe off the secondary drain. This way you can see how it's working, it's really not needed. Water going through that pipe should only be a trickle anyway.

 

[reeflink]

There should be at least probably 4 inch between the primary drain and a secondary drain. This way you don't get that Cyclone sucking sound.
The second thing is the secondary drain if it's raised up will raise that water level inside that little box so the water doesn't fall in 1.25 off the weir.
Like I said before, lose that "u" shaped pipe off the secondary drain. This way you can see how it's working, it's really not needed. Water going through that pipe should only be a trickle anyway.

There isn’t to much more room to raise the durso pipe . I might be able to get .5” but that is pushing it. Honestly .25” is probably it.

 

[Dburr1014]

Can this be raised 3/4 of an inch?

 

[Dburr1014]

There isn’t to much more room to raise the durso pipe . I might be able to get .5” but that is pushing it. Honestly .25” is probably it.

Then you need to get a longer pipe.
Edit: can't stop the waterfall splashing noise without stopping the waterfall. Putting a sponge in their might cause more problems, like an overflow tank

 

[JNalley]

There should be at least probably 4 inch between the primary drain and a secondary drain. This way you don't get that Cyclone sucking sound.
The second thing is the secondary drain if it's raised up will raise that water level inside that little box so the water doesn't fall in 1.25 off the weir.
Like I said before, lose that "u" shaped pipe off the secondary drain. This way you can see how it's working, it's really not needed. Water going through that pipe should only be a trickle anyway.

Why do you keep replying to me, but responding to the OP? lol...

 

[JNalley]

There isn’t to much more room to raise the durso pipe . I might be able to get .5” but that is pushing it. Honestly .25” is probably it.

according to the first pic, you have nearly an inch you can go up from the top of the Durso to the cover on the top...